Vegetable Oil May Not Reduce Your Risk of Heart Attack
Now, data from a 50-year old study shows that may be so… but that switching from butter to corn oil doesn’t make a difference in terms of your risk of heart attack.
The original study was conducted between 1968 and 1973. However, the data wasn’t published until 1989.
At the time, the investigators reported that replacing saturated fat with corn oil, which is rich in linoleic acid, did lower cholesterol levels.
However, the participants with the greatest reduction in cholesterol had higher, rather than lower, risk of death. Additionally, the switch made no difference when it came to risk of heart attack and deaths due to heart attack.
A team of current day researchers ran across this study, and they found that some of the important analyses the original investigators had planned were missing from the paper.
With the help of one of the original researchers’ sons, the team recovered much of the raw data from the study. Then, they used it to perform the missing analyses.
They were able to confirm the cholesterol-lowering effect of the dietary intervention. But in recovered autopsy records, they found the corn oil group had almost twice the number of heart attacks as the control group.
Additionally, women and patients older than 65 experienced roughly 15 percent more deaths during the trial when compared to the control group.
The team also recovered unpublished data from a similar trial. And the results were much the same. They found more cases of heart disease and death among patients who received a linoleic acid intervention (safflower oil), compared to controls.
“Altogether, this research leads us to conclude that incomplete publication of important data has contributed to the overestimation of benefits–and the underestimation of potential risks–of replacing saturated fat with vegetable oils rich in linoleic acid,” said co-first author Daisy Zamora.
The researchers note that small amounts of linoleic acid are essential for health. However, high intakes are not natural in the human diet. In fact, some studies suggest that these oils cause inflammation, which is a risk factor for heart disease. Additionally, they may promote plaque build-up in the arteries.
Lowering cholesterol with veg oils may not curb heart disease risk or help you live longer. Press Release. BMJ via EurekAlert. Apr 2016.
Did butter get a bad rap? Press Release. University of North Carolina Health Care via EurekAlert. Apr 2016.